One commercially successful type of draft gear mechanism is shown in U.S. Pat. No. 2,764,300. This type of draft gear mechanism employs a friction wedge and friction shoes in conjunction with a pad follower and rubber pad units. The wedge and shoes are mounted within a front constricted friction bore section of a casing, while the follower and pad units are mounted within a larger main body portion of the casing. This arrangement offers a highly efficient shock absorber.
However, this prior art draft gear mechanism has one serious shortcoming. Because of the large size of the rubber pad units, they can not be assembled through the constricted front section, and a removable rear wall is provided so that the follower and rubber pad units may be assembled through the rear of the casing. The removable rear wall considerably impairs the integrity of the rear end of the casing and hence has a deleterious effect on the service life of the draft gear mechanism under heavy load conditions.